1. Field of the Invention
Example embodiments of the present invention relate to a wiring structure in a semiconductor device and a method of fabricating a wiring structure in a semiconductor device. More particularly, example embodiments of the present invention relate to a wiring structure having a plug extending through insulation layers and a method of fabricating the wiring structure.
2. Description of the Related Art
As semiconductor devices are required to have more rapid response speeds and higher storage capacities, manufacturing technology has been developed to produce highly integrated semiconductor devices with improved reliability, etc. A dynamic random access memory (DRAM) has been widely used as a semiconductor memory device in various electronic and electric apparatuses because of the relatively rapid response speed and high storage capacity. DRAM devices generally include unit memory cells, each of which includes an access transistor and a storage capacitor.
As design requirements for the DRAM devices have generally required decreased size, the unit memory cells of the DRAM devices occupy significantly reduced areas. The capacitor therefore may not have a desired high capacitance. To improve an effective area of the capacitor, the structure of the capacitor has been changed from a planar type to a stacked type, a trench type, a cylindrical type, etc.
A cylindrical capacitor of a semiconductor device, in particular, makes electrical contact with a contact region of an access transistor. Therefore, a portion of the capacitor depends on formation of the transistor on a substrate. Adjacent capacitors may be connected to each other, potentially causing electrical failure, because the area allowed for formation of the capacitors is very small. Further, a capacitor may not be properly connected to a corresponding access transistor when the capacitor is formed in a very small area of the substrate.
Recent designs provide for larger areas for plugs on substrates to ensure proper electrical contact between transistors and capacitors, even though the capacitors are very small. Alternatively, additional landing pads, relatively large in size, may be formed on plugs electrically connected to transistors in order to improve the electrical connections between the transistors and the capacitors.
However, bridges may be easily formed between adjacent plugs, thereby causing electrical failures or shorts between the adjacent plugs, when the plugs are larger. Further, manufacturing processes for forming capacitors may be complicated when the landing pads are also on the plugs, and alignment errors between the landing pads and the plugs may result.